A/N: Hit a bit of a rough patch with my current fic so I decided to write this up as a bit of a fun characterisation exercise. Like my Three Patch Problem fic, this is just me taking a stab at providing some reasonable explanations for Sherlock's behaviour in the show, as well as making sure my personal characterisation fits in with canon. Fun times for everybody!
"Oh Sherlock, what have you done?"
He's alarmed. Sociopath or not, he doesn't like seeing other people cry. Least of all Mrs. Hudson, who's only ever been kind to him and doesn't deserve to be upset over whatever trouble he's caused her now. He bolts up the stairs and flings open the door to find a crew of uniformed police officers milling about in his (their?) sitting room, searching-lifting-moving-touching his things. He hates it, wants to scream at them to stop but forces himself not to. Instead he just snaps angrily at the smirking, silver-haired man lounging placidly in his chair like he thinks he bloody owns the place.
Damned Lestrade. Sherlock's never been able to figure him out. One minute he's kind, accommodating, almost fatherly and the next he's... argh he's in his flat doing a bloody drugs bust in front of the first person he's met in ages who might possibly be able to put up with him and, and just- god, Lestrade, why now? Why couldn't he have just called or come over later to lecture him privately or complained to his brother or done literally anything else? Carting all these people into his home, humiliating him in front of his new flatmate (who probably won't want to be his flatmate at all anymore, not after this, but he refuses to think about that). It's just bullying, plain and simple.
He rants at Lestrade and the man just smiles, smug and infuriating. Bastard. And oh god, John's trying to defend him. No, John. Just... no. Just shut up right now. He glances around and sees Lestrade's smirking grin grow wider, almost chuckling as the naive doctor comes to the misguided defence of a man he really doesn't know anything about at all.
All the officers who've been on the force long enough to have seen Sherlock high are giving each other coy little smirks. They think John's about to leave. Think the second he finds out the truth he'll walk out and leave Sherlock to face the consequences of his habit and his freakishness but no no no, Sherlock knows John won't do that (hopes he won't, hopes to god but-) but the warning stare he fixes on the man is nonetheless tinged with just a hint of worry.
John is flabbergasted. You?
Yes, me, John because you don't know the first thing about me and, and just- just shut up.
He rounds on Lestrade again, because he doesn't want to see the moment when John realises how pathetic he really is. Discovers Anderson of all bloody people rifling through his kitchen cabinets. His stomach clenches as it always does at the sight of that horrible, weasel-like face. Too evocative of old memories for comfort, too similar to- no no no god, all these people in his flat get them out!
His usual defence mechanism of lobbing scathing insults kicks in and he snipes acidly at both Anderson and his trampy harlot of a lover Donovan before shoving his hands in his pockets and turning to pace in agitation. Anxiety is creeping up his spine, making his insides twist uncomfortably. John still hasn't spoken since being told to shut up (just following orders? or is he disappointed, preparing to walk out?), the officers are too close to what he dearly hopes they won't recognise as a pre-mixed solution of cocaine sitting next to the chemistry supplies (it's just there for emergencies he hasn't used any in months he's doing fine) and he snaps at Lestrade. Shows the nicotine patch because see I've even stopped smoking isn't that enough to prove I'm trying but Lestrade just shows his too, negates Sherlock's accomplishment with his own because of course Lestrade's also gone off cigarettes. Like it's so simple even an ordinary sod like Lestrade can do it. He rolls his sleeve back down and turns to glare viciously at the police mucking about in his kitchen.
Lestrade seems to have finally clued in to how upset Sherlock's getting and changes the subject to focus on the case instead, tactfully giving the detective an excuse to think of something else before the anxiety eats him alive. Sherlock latches on to the mental escape route and allows his brain to completely switch gears on him. It helps, he's focused on clues now and the people crowding in on him fade to a backdrop.
Until, of course, Anderson pipes up. That bloody weasel-faced- ugh. Calls Sherlock a psychopath. He is not. The stupid bastard doesn't even know what the word means. He snaps back a retort quickly before switching back to the murder case, turning away from the man before his train of thought has a chance to get derailed.
The victim scratched the name of a stillborn daughter on the floor. Why? A stillborn, meaning there wouldn't have been enough time to form more than a rudimentary emotional connection. And fourteen years ago at that! So why would she bother? Can't be sentiment, she might have had a bit of lingering depression over the incident but not to the level of- no, there has to be another reason. Nobody would still be upset after so long, not enough to cause themselves physical pain in their final moments etching out a name that would serve no useful purpose. John doesn't see and Sherlock whips around from his pacing to snap at him because it's obvious. She had to have another motive. The stillbirth was ages ago, John! Why would she still be upset?
And just like that everyone is staring at him.
Oops, he thinks, feeling the room grow silent. He shifts uncomfortably, nervous under the scrutiny. Damn. Did he cock up somehow? Forgot to obey some social convention? Should he have just gone with their stupid assumptions, pretended to care even though everyone in the bloody room should know perfectly well that no woman would go to such lengths for a child she never even got to meet? Probably, he thinks. But then he's not sure. No way to tell if they're staring because of what he said or if he's just gone and done something freakish without noticing again. John would know. The man for some reason still seems inclined to talk to him, so he takes the chance and asks.
Bit not good, apparently.
Alright, then.
Argh but no, no god damn it why? Everyone should be able to see, should be able to- he launches into an explanation. What would you say if you were about to die? Forgets for a moment that John would have first-hand experience, and that causes his argument to fall a bit flat, but wait no it doesn't because John's smart but not really all that clever, not like the victim must have been, so it doesn't count. Drops the subject, useless, he has to think. There has to be some reason she would...
He returns to pacing, not even registering the insulted look on the doctor's face, and like she's just been waiting for the worst possible moment Mrs. Hudson shows up nattering about a taxi. Didn't order a taxi, fuck's sake what would he even need one for go away. Then she and John start blathering on about nothing so pointless and he can't bloody think because there's too many people and SHUT UP EVERYBODY JUST SHUT UP.
Yells at Anderson to turn around, because his face is too much like his and it's distracting and if there's one thing he doesn't need to think about it's that. Of course the moron argues but for once Lestrade deigns to be helpful and confirms the order, adding on instructions for everyone else to be silent as well.
The room grows marginally quieter, except for Mrs. Hudson who's still on about the bloody taxi so he shouts at her and she scampers off. He doesn't have time to feel bad about yelling, because oh! Oh, god yes suddenly it all makes sense. That's why- he grins in relief. Clever. Very clever. And it confirms his position on the whole miscarriage thing (though that had never really been in question anyway.)
Explaining makes him feel better, shows off how brilliant he's managed to be and proves that yes, yes I'm still right I'm always right even when you bastards break into my flat and give me an anxiety attack I'm still bloody right- but like usual nobody else understands. God, how? It's so obvious! He tries to explain enough for them to realise it themselves but of course all he gets for his trouble is a room full of vacant stares. Christ, what's it even like to be so stupid? Must be so relaxing, not knowing all the things he knows, little brains full of boring, mundane fluff instead of searing fire.
John gets him back on track, snapping at him before he can really get going on another patronising diatribe, and he manages to convey what 'Rachel' means without unduly insulting anyone (well, except Anderson, but he's a special exception). He leaves John to get the coordinates of the phone while he tries to talk some sense into Lestrade concerning how to handle the investigation from here.
In less than a minute John speaks up hesitantly, almost failing to get Sherlock's attention before he finally takes notice and strides over, only to stop short in confusion at the data on the laptop screen. The phone's... here? How can it be- no, it can't. He would have noticed it. Has to be some other explanat- as he turns to start pacing again he catches sight of Mrs. Hudson hovering in the doorway, the cabbie he never called for lurking behind her. Oh.
... OH! Yes, that's it! Suddenly everything clicks into place, and it's brilliant. The taxis, of course.
A text alert makes his phone vibrate in his pocket, cutting him short before he gets a chance to convey his realisation to the others.
COME WITH ME, it says.
There's only one person it can be from. He considers for the barest moment telling John, or Lestrade even, that their murderer is currently standing behind his landlady at the door. Immediately tosses the notion aside. What would be the point? John isn't going to stick around much longer, not after tonight, and certainly won't care if Sherlock gets himself killed following a lead. Lestrade, of course, has quite thoroughly lost all right to be informed of anything Sherlock does for a good long while.
Going with the cabbie might be dangerous, might be suicidal, but the spike of adrenaline shooting through his veins gives him his decision before he's even had time to think it through. All at once the world seems to slow down on him, thoughts calming in the wake of discovery. The giddy high of fresh anticipation. It's almost like cocaine... almost, but so much better. So much more vibrant. Everything around fades to static, leaving him caught in a dreamlike state as he lowers his phone and walks toward the door.
John tries to stop him. Where are you going?
He replies with some half-hearted excuse, scarcely aware of what he's even said. It doesn't matter, John's hardly going to follow him.
Without so much as a backward glance, Sherlock leaves the flat.
A/N: Any other scenes you'd like to see written up this way? I find it ridiculously amusing. Present tense internalised Sherlock is like crack to me, seriously.
(PS. There's a somewhat subtle reference to one of my other fics in here. If anyone catches it I'll award you fifty internet points.)